This invention relates to ether carboxylates useful as chelants, sequestrants and detergency builders.
The property possessed by some materials of improving detergency levels of soaps and synthetic detergents and the use of such materials in detergent compositions is known. Such cleaning boosters are called "builders" and such builders permit the attainment of better cleaning performance than is possible when so-called unbuilt compositions are used. The behavior and mechanisms by which builders perform their function are only partially understood. It is known that good builders must be able to sequester most of the calcium and/or magnesium ions in the wash water since these ions are detrimental to the detergency process. However, it is difficult to predict which class of compounds possess useful combinations of builder properties and which compounds do not because of the complex nature of detergency and the countless factors which contribute both to overall performance results and the requirements of environmental acceptability.
Sodium tripolyphosphate (STP) has been found to be a highly efficient cleaning and detergent builder and this compound has been widely used for decades in cleaning and detergent formulations. Indeed, millions of pounds of STP are used each year in cleansing formulations because of its superior builder qualities. However, because of the recent emphasis on removing phosphates from detergent and cleaning compositions for environmental reasons, the detergent and cleaning industry is now looking for materials suitable for use as builders which do not contain phosphorus, and which are environmentally acceptable.
A large number of materials which do not contain phosphorus have been evaluated for use in detergent and cleaning formulations as a builder, and some of these materials have been ether carboxylates. As an example, U.S. Pat. No. 3,865,755 discloses the use of carboxymethoxy tartronate as a chelant, sequestrant and detergent builder. U.S. Pat. No. 3,993,574 discloses the use of this compound with sodium carbonate in detergent formulations, and other patents disclose the preparation of that ether carboxylate. In addition, application Ser. No. 736,962 filed Oct. 29, 1976 related to ketal polycarboxylated compounds, methods for making such compounds and compositions employing such compounds is related to the polycarboxylates of the present invention.
Although satisfactory results are achieved using the polycarboxylates set forth above, there remains a need for new and structurally different polycarboxylates to satisfy specialized applications in detergent formulations. Hence, those skilled in the art of detergent formulation are constantly looking for polycarboxylates for use as chelants, sequestrants and detergency builders in such formulations, and the present invention provides to the art a class of polycarboxylates that are structurally different from the prior art suitable for use in such applications.